Film Critique of the Lower Extremity - Part 3


Reviews anatomy and critique of the ankle joint, foot, and toes.

Author: Nicholas Joseph Jr. RT(R)(CT)

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Radiographic Critique of the Ankle

Diagnostic Criteria for Imaging the Foot

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Radiographic Film Critique of the Lower Extremity: Part 3

The Ankle and Foot

Written by Nicholas Joseph Jr. RT(R)(CT) B.S. M.S



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Ankle and foot injuries are fairly common; over 2 million persons are treated each year for ankle injuries alone. Because most injuries to the ankle occur by accident it does not matter if one is a well-conditioned athlete or a sedentary person, injuries do occur. However, being overweight or wearing high-heeled shoes are known to increase risk. In this section we will discuss how to critique radiographs of the ankle, foot, and heel. Keep in mind that the ankle, foot, and heel are distinct anatomic regions that require particular radiographic projections to demonstrate injury. Therefore, a good clinical assessment by the requesting physician is required. As radiographers we commonly see conditions affecting the foot or heel that are referred to the “ankle.” So it is common to consult with the ordering physician when the area of interest is ambiguous. Fractures of the ankle are second only to wrist fractures in frequency. As we shall see when we discuss the anatomy of the ankle that it is capable of only planar flexion and dorsiflexion. Injury occurs because of severe eversion, inversion, or a combination of rotational forces. Understanding how injury occurs is part of what inspires a good radiographer to produce consistent properly positioned radiographs of the ankle.

The foot is an especially interesting area radiographically. Anatomically, the foot is composed of the tarsal bones, metatarsals, phalanges, and sesamoid bones. Often it is clinically divided into the forefoot that includes phalanges and metatarsals; the midfoot refers to the three cuneiform bones, the cuboid, and the navicular; and the hindfoot being the talus and calcaneus. The anatomical platitude of the foot requires that the talus be radiographed on the ankle views. The heel and foot also require specific radiographic examinations to properly demonstrate them. Now let’s consider some basic anatomy of the ankle and foot relative to radiographic imaging.

The Ankle Joint

The ankle joint is a hinge type joint composed of three bones: the distal tibia, distal fibula, and talus. Extending down along the medial talus is the medial malleolus of the tibia. At the expanded distal end of the fibula is the lateral malleolus, which extends alongside the lateral portion of the talus. An articular surface on the superior surface of the talus called the trochlea articulates with the broad distal inferior articular surface of the tibia. The lateral malleoli of the fibula, the medial malleolus of the tibia along with the horizontal plate of the tibia form a unique “box joint,” which is called the ankle mortise. The ankle mortise is a deep-socketed opening into which the talus fits forming a hinge type joint. The ankle mortise is not seen on the true frontal view of the ankle because the three-part articulation of the tibia, fibula, and talus along the lateral mortise is offset. The distal fibula is aligned about 1 cm posterior with the talus in relationship to the distal tibia. The lateral malleolus extends more distally than the medial malleolus by approximately 1 cm. Therefore, the true lateral projection of the ankle is not achieved by superimposing the medial and lateral malleoli. To demonstrate the ankle mortise a 15-degree internal rotation of the hip to align the foot and ankle, called the mortise position is required. This will demonstrate the ankle mortise opened without overlap of the distal fibula or tibia upon the talus.


These two axial CT images demonstrate the relative locations of the medial malleolus of the tibia and lateral malleolus of the fibula to the talus. The axial CT image on the left demonstrates the relative positions of the medial and lateral malleoli to the talus. The lateral malleolus is seen more posterior than the medial malleolus. A line drawn through the medial malleolus to the true coronal anatomical plane and a second line drawn through the malleoli (intermalleolar plane) will be offset 15-20 degrees. To demonstrate the ankle mortise the intermalleolar line is brought parallel to the coronal plane. The CT image on the right demonstrates the ankle joint in a true lateral to show the anterior/posterior relationship of the medial and lateral malleoli. The lateral malleolus articulates more posterior with the talus than the medial malleolus. The broad anterior tubercle of the distal tibia is profiled on the lateral view.
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These two 3-D CT images demonstrate the ankle mortise. On the left the fibula (A) and tibia (B) are labeled; these two bones form a box joint called the ankle mortise. On the right the left ankle joint is seen with the talus (T) within the ankle mortis. The left ankle joint is seen opened because the hip is internally rotated 15 degrees so that the ankle mortise is seen unobstructed. The ankle joint is a hinge-type joint capable of flexion and extension.
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Two images are presented to demonstrate the anatomy of the distal leg and ankle joint. On the left is a 3-D volume rendered CT image of the right ankle from the AP view. On the left is a radiograph of the left ankle. The following structures are demonstrated on both images: the distal fibula (A), distal tibia (B), lateral malleolus of the fibula (C), medial malleolus of the tibia (D), and the talus, a bone of the foot (E).
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These two CT volume rendered 3-D images show the structure of the ankle joint. On the left the two bones of the leg, the fibula (A), and tibia (B) are shown to demonstrate the “box” joint called the ankle mortise. The talus (C), which is the third bone of the ankle, is shown within the ankle mortise on the image on the right. Other labeled structures are the medial malleolus (E), lateral malleolus (D), and ankle mortise (arrows).

The ankle joint participates in movement of the lower limb and contributes to its stability. When standing the weight of the torso is most stable when the ankle is in doriflexion. There are two types of motions that take place at the ankle joint, dorsiflexion and plantar flexion. When the dorsal surface of the foot is flexed towards the anterior tibia, the ankle is in dorsiflexion. The importance of dorsiflexion is that it allows the foot to contact the ground heel first during “heel strike” phase of gait. Dorsiflexion of the ankle joint positions the foot to clear the ground during the swing phase of gait. Plantar flexion on the other hand extends the plantar surface of the foot away from the leg. Plantar flexion is the position of the ankle when the toes contact the ground first and the heel is raised to provide propulsion of the limb. This movement lifts the limb and provides forward swing during gait.

Ankle injuries occur as a result of extreme eversion (abduction), inversion (adduction), or rotational movement of the ankle and the foot is in supination or pronation. An example of this is the act of stepping into a pothole unexpectantly causing extreme inversion of the foot. Eversion, inversion, and impaction forces are all capable of causing malleolar fracture. When the talus is forcefully shifted within the ankle mortise an impaction force has occurred. Some distinct fracture patterns are seen with these forces. For example, an oblique fracture line characteristically represents impaction injury; avulsive force causes a horizontal malleolar fracture line. Keep in mind that not all injuries result in bone fracture, soft tissue injuries such as sprain or stretched ligaments also occur. When imaging the ankle it is important that soft tissue structures be properly demonstrated. This is because disruption of one or more ligaments of the ankle or foot can be as destabilizing as a bone fracture. With the proper positioning and exposure of the radiograph soft tissue swelling or subtle cortical avulsion can be diagnostic. Let’s review some of the soft tissues of the ankle so that their significance to imaging is fully appreciated.

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The 3-D CT image on the left demonstrates the foot in plantar flexion. Plantar flexion is the position of the ankle when the toes contact the ground first and the heel is raised to provide propulsion and forward swing during gait. The 3-D CT image on the right shows some of the tendons and ligaments of the foot.

A basic knowledge of the ligaments of the ankle is fundamental to understanding the pathophysiology of ankle injury and its imaging. There are several tendons that move the ankle/foot apparatus together with ligaments that stabilize its movements. These soft tissue structures are prone to injuries such as sprain, tear, and to over stretching. Tendons are very similar to ligaments, the difference is that ligaments attach bone to bone, and tendons attach muscle to bone. Relatively strong collateral ligaments support the ankle joint. They extend from the malleoli to the calcaneus and talus. Ligaments on the lateral side of the ankle are more commonly sprained than the medial ones because they are generally weaker. The lateral ligaments of the ankle when over stressed can cause inversion injuries, whereas sprain of the medial ligaments can cause eversion injuries. Dislocation and/or fracture are fairly common results of excessive stress on the joint.

The two main ligament groups of the ankle are the lateral collateral ligament (LCL) and the medial collateral ligament (MCL, also called the deltoid ligament). The lateral collateral ligament is actually composed of three ligaments: the calcaneofibular ligament together with the anterior and posterior talofibular ligaments. The anterior and posterior talofibular ligaments are horizontal bands that connect the talus to the fibula. The calcaneofibular ligament is a rounded ligamentous band that extends from the inferoposterior tip of the fibular malleolus to a tubercle on the lateral side of the body of the calcaneus. It is deep to the peroneus longus and peroneus brevis muscles.

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This 3-D volume rendered CT image demonstrates some of the ligaments of the lateral collateral ligament compartment. The anterior talofibular ligament (green), lateral talocalcaneal ligament (orange), and calcaneofibular ligament (red) are shown. These ligaments stabilize the foot against inversion injury.

The medial side of the ankle contains a stronger denser ligament arrangement composed of the medial collateral (deltoid) ligament. Three loose arrangements of deep and superficial fibers spread from the medial malleolus to attach to the talus, navicular, and sustentaculum tali of the calcaneus. Uniting the tibia and fibula along their course is a deep extension of the interosseous ligament called the interosseous membrane. When imaging the ankle one should keep in mind that radiological interpretation includes evaluation of ligamentous injury. Therefore, all surrounding soft tissue including the skin should be included on all ankle projections.

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The yellow band on the 3-D CT image above represents the distribution of the deltoid ligament. The medial side of the ankle is stronger than the lateral side due to the strong dense structure of the medial collateral ligament. The MCL attaches the medial malleolus to the talus, navicular, and calcaneous bones.

Ankle injuries are cause mostly by indirect loading when the leg rotates around a stationary foot. The most common injury is lateral ankle sprain. Excessive loading on the ankle causes the talus to break open the mortise. Indirect ankle injury is caused by excessive inversion, external rotation, abduction, and axial compression. Ankle fractures can be simply classified by the number of malleolar fractures, e.g. unimalleolar, bimalleolar, or trimalleolar. A trimalleolar fracture is a term for a fracture involving the lateral, medial, and posterior malleoli. Most fractures are named or classified by direction of the fracture line through bone, or by the shape or number of fragments. A complete fracture line goes through the entire cross section of the bone, whereas an incomplete fracture describes a break involving only one side of the cortex. Three or more divisions of a bone is classified as a comminuted fracture.

Directionally classified fractures such as transverse, oblique, spiral, and longitudinal are terms that describe the fracture relative to the long axis of the bone. The term impacted refers to the cortical shaft being driven into cancellous bone by the fracture force. An avulsion fracture describes a small chip of bone that breaks away from the bone during dislocation of the joint or from significant ligament injury. A special type of fracture called a pathological fracture describes a fracture through diseased bone. This type of fracture does not heal like normal bone because the disease process must be arrested in order for one healing to be successful.

Fractures in children do occur, but are generally not as serious as in adults because their bone is more flexible. A plastic fracture is an example of how young soft bone responds to injury by bending, but not breaking the bone or its cortex. A greenstick fracture occurs when the cortex on only one side of the bone breaks. A torus fracture is a type of greenstick fracture in which the cortex folds back onto itself leaving the classical buckled cortex sign. Sometimes the bone will have a classical angulated appearance or bowing of the bone. Another type of fracture that occurs in children is the epiphyseal fracture. Epiphyseal fracture occurs through an unfused area of the epiphysis. Because this type of fracture often presents without displacement a comparison radiograph of the opposite unaffected bone may be needed to make the diagnosis.

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Inversion of the foot caused by inward rotation along its long axis results in loading on the lateral ligaments and lateral malleolus. Initially the anterior talofibular ligament may tear followed by the calcaneofibular ligament. The radiograph on the left shows soft tissue swelling along the malleoli, which is a roentgenographic sign. In most cases the talus may be tilted causing simple sprain. The 3D surface rendered image on the right shows the result of extreme loading in which the talus has dislocated and caused a break in the ankle mortis and fracture of the lateral malleolus.

The Foot (Pes)

The foot-ankle relationship is important because the entire weight of the body is transferred along this axis. Smooth transference of weight is important for stability during gait, as this motion is coupled to foot lift during locomotion. Wedged bones of the foot are arranged in arches that facilitate support during weight bearing and locomotion. Another concern is that when walking or running the foot must remain in contact with the ground even when the ground is uneven. Because portions of the foot usually contact the ground unevenly, the foot requires balance and support. To reinforce support for balance the bones of the foot are arranged into a transverse arch. Longitudinal and transverse arches orchestrate foot and ankle transitions during the propulsion phase of gait. These arches also participate in moving the foot upwards from the ground and propel the body forward during locomotion. The three arches of the foot are the medial longitudinal arch, lateral longitudinal arch, and transverse arch. Weight-bearing views are useful when evaluating the arches of the foot.

The foot contains 26 bones conventionally divided into three groups: tarsals (7 bones), metatarsals (5 bones), and phalanges (14 bones). The tarsal bones are the calcaneus, talus, navicular, cuboid, and three cuneiforms (medial, intermediate, and lateral). The bones of the foot are functionally divided into three segments called the hindfoot, midfoot, and forefoot that can further describe arches and functions of the foot during gait. The hindfoot is comprised of the calcaneus and talus. The midfoot is comprised of the navicular, cuboid, and three cuneiform bones. The metatarsals and phalanges (digits) make up the forefoot. The bones of the foot are slightly curved forming the three mentioned arches. These arches function to absorb the weight of the body and distribute forces to the ground.

The hindfoot is composed of the talus (also called the astraglus) and the calcaneus (also called the os calsis, or heel). Although the hindfoot consists of only two bones, they participate in three functional joints: the ankle joint, subtalar and talonavicular joints. The talus and calcaneus share a special relationship that is important radiographically. The talus rests on top of the calcaneus with its dome forming the pivot of the ankle joint. Some of the more prominent parts of the talus are its dome, body, neck, and three facets on the lower side for articulation with the calcaneus. The body of the talus is the largest part. The posterior portion of the talus has a posterior protrusion that can develop separate from the body as a small accessory bone called the os trigonum. A constricted portion of the body, called the neck, projects forward ending in an expansion called the head. The head articulates with the navicular bone anterior to it forming the talonavicular joint. The talocalcaneal articulations consist of three smooth facets on the underside of the talus. These form the subtalar joint with the calcaneus. A function of the subtalar joint is to conform the foot to irregular surfaces during gait. It also stabilizes the ankle joint and reduces stress on the foot during weight bearing.

The calcaneus is the largest tarsal bone. Its upper surface contains a posterior, middle, and anterior facet. These facets articulation with the corresponding facets on the lower talar surface to from the subtalar joint previously described. A groove formed by the subtalar joint called the sinus tarsi is a channel between the talus and calcaneus. The calcaneocuboid and talonavicular joints are together referred to as the midtarsal joint. The midtarsal joint forms the boundary between hindfoot and midfoot.

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Demonstrated on this dorso projection of the foot are: the phalanges (A), metatarsal row (B), medial cuneiform (C), intermediate cuneiform (D), lateral cuneiform (G), navicular (E), talus (F), cuboid (H), and calcaneus (I). The seven tarsal bones are the three cuneiforms, cuboid, navicular, talus, and calcaneus.

The calcaneus (heel bone) is the largest bone of the foot. Its most posteroinferior part contains a process called the tuberosity to which large tendons that move the foot attach. The calcaneus articulates with two bones, the talus superiorly, and the cuboid anteriorly. The superior articulation forms the subtalar (talocalcaneal) joint. The subtalar joint is really three articulations with their specific facets. There is a large posterior facet and smaller middle and anterior facets. A deep groove, called the calcaneal sulcus, can be seen between the middle and posterior facets. A prominent bony process can be seen on the medial proximal portion of the heel bone called the sustentaculum tali (a name that literally means support for the talus). The lateral aspect of the calcaneus is a less prominent bone ridge called the trochlear process. This is best seen on the axial view of the calcaneus.

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These two 3-D volume rendered CT images of the foot show the heel from the superior and inferior viewings. Some structures on the calcaneus are labeled: anterior facet (A), middle facet (B), posterior facet (D), sustentaculum tali (C), and tuberosity (E).
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These two 3-D CT images show the calcaneus from the medial (left) and lateral (right) sides. The three articular facets can be seen in both views as well as the articular regions where it articulates with the talus superiorly and cuboid anteriorly. A blue arrow points to the prominent shelf-like sustentaculum tali that support a portion of the talus.

Arches of the Foot

The three arches of the foot are so named according to the area they support during standing and locomotion. The transverse arch shapes the medial to lateral contour of the foot. The medial and lateral longitudinal arches provide longitudinal support along their respective margins. The medial longitudinal arch is formed by the calcaneus, talus, navicular, three cuneiforms, and the first, second, and third metatarsals. It is a pronounced longitudinal curvature seen from the medial side of the foot. The longitudinal arch is the spring system of the foot having a medial and lateral component. The medial side is the most pronounced portion of the longitudinal arch. The major function of the medial arch is to transfer weight to the metatarsal heads and calcaneus. The lateral longitudinal arch is formed by the cuboid, fourth and fifth metatarsals, and tuber calcaneus (bottom of the heel). The lateral arch is slightly curved and functions to transfer weight to the ground.

The transverse arch is arranged along the plantar surface of the distal tarsal bones and the tarsometatarsal joints. It is a concave arch formed by the wedge-shaped cuneiforms, cuboid, and base of the five metatarsals. It performs like a suspension bridge support that absorbs medial/lateral transitions of the foot.

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This 3-D CT image shows the medial surface of the foot and those structures that form the medial longitudinal arch. The medial arch is formed by the calcaneus (A),talus (B), navicular(C), the medial cuneiform (D), first, second, and third metatarsals. The head of the third metatarsal (E) is labeled. The medial arch is very pronounced having distributed points of force to the metatarsal heads and heel.
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This 3-D CT image demonstrates the lateral surface of the foot and lateral longitudinal arch. The lateral longitudinal arch is formed by the cuboid, fourth and fifth metatarsals, and tuber calcaneus. The longitudinal arch on the lateral side is slight relative to the medial arch. It functions to transfer forces of weight from the body to the ground. Labeled structures are: calcaneus (A), tuber calcaneus (B), cuboid (C), and base of the fifth metatarsal (D).

The joints of the foot are also of importance and are frequently involved in bone injury. Tarsal joints (aka: intertarsal joints) consists of the subtalar joint and transverse tarsal joints. These joints are capable of flexion, extension, inversion and eversion of the foot. The intertarsal joints are articulations between adjacent tarsal bones. They are synovial joints having rotational and/or gliding movements. These joints produce most of the foot’s movement, especially between the hind and midfoot. The subtalar joint, for example, is an articulation between the talus and the calcaneus. A large concavity called the tarsal sinus separates three articulations of the talus with the calcaneus, which is divided into anterior and posterior portions; the posterior margin is the subtalar joint. The subtalar joint supports inversion and eversion of the heel. Within the tarsal sinus is an interosseous ligament called the talocalcaneal ligament. It holds the talus and calcaneus together during movement. The transverse tarsal joints are actually a combination of three separate articulations that include the talocalcanealnavicular, calcanealcuboid, and talonavicular joints. Movements of the transverse tarsal joints allow the forefoot to move on the midfoot. Many ligaments hold the foot joints together and stabilize alignment of the bones. Several common foot alignments are commonly described: pes plantus or flat foot, pes cavus or exaggerated arch, pes varus or inverted and adducted foot, or pes valgus (everted and abducted foot).

Radiographic Anatomy Review

Some of the common projections of the ankle and foot are presented below. These radiographs are labeled to help provide a review of those structures you should be familiar with as a clinical radiographer. Identifying and writing your answers to all parts labeled can help you accomplish a good practice review. Then review the diagnostic criteria for each view prior to looking at selected radiographs of the ankle and foot.

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These two radiographs demonstrate basic radiographic anatomy seen on the AP and lateral projections of the ankle. Labeled are the fibula (A), lateral malleolus (B), mortise joint of ankle (C), talus (D), medial malleolus (E), tibia (F), posterior malleolus of talus(G), calcaneus (H), navicular (I), superimposed cuneiforms (J), cuboid (K), base of fifth metatarsal (L). The white arrows point to the ankle joint and the yellow arrow to the sinus tarsi.
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The fat pads of the ankle are best seen on the lateral view. The anterior pretalar fat pad is crescent and lies against the neck of the talus (white arrows). A teardrop like soft tissue density displacing this fat pad is greater than 80% sensitive and 90% specific for underlying ankle fracture. Therefore, the anterior pretalar fat pad must be demonstrated on radiographs. The foot is dorsiflexed 90 degrees to the leg to show displacement of the fat pads. The posterior pericapsular fat pad, which is part of Kager’s fat pad, should also be visualized (blue arrowheads). An accessory bony ossicle (os trigonum) is also noted (yellow arrow).
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This oblique view of the right foot demonstrates radiographic anatomy of the foot. Labeled structures are: distal phalanx of 1st digit (A), interphalangeal joint of 1st digit (B), proximal phalanx of 1st digit (C), metatarsophalangeal (MP) joint of 1st digit (D), head of 1st metatarsal (E), superimposed medial and intermediate cuneiforms (F), navicular (G), talus (H), neck of calcaneus (I), lateral cuneiform (J), cuboid (K), fifth metatarsophalangeal (MP) joint of 5th digit. The digits are numbered from medial to lateral (I-V). The sinus tarsi and a portion of the subtalar joint is demonstrated at the blue arrow.
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Labeled structures on this lateral projection of the foot are: distal tibia (A), distal fibula (B), talus (C), calcaneus (D), subtalar joint (E), navicular (F), superimposed cuneiforms (G), cuboid (H, and base (I), and head (J) of 5th metatarsal. Yellow arrows point to the epiphysis in this young person’s heel. A red asterisk indicates the superimposition of the medial and lateral malleoli on the talus.
Diagnostic Criteria for the AP, Lateral, and Mortise Views of the Ankle


    Four views of the ankle are commonly made to evaluate for fracture, dislocation, instability, or disease. These are the AP, mediolateral, 15-degree mortise, and 45-degree external oblique view. The 45-degree oblique is an institutional preference and is performed as either an internal or external rotation of the foot/ankle. The diagnostic criteria for each of these projections are given below:


      The AP Projection

    1. The AP ankle view should demonstrate from the distal third of the tibia-fibula to the proximal half of the metatarsals. This includes the entire talus, distal tibia and fibula, and base of the metatarsals.
    2. The medial mortise and tibiotalar joints should appear open, but the lateral mortise will be closed due to a superimposed distal fibula on the lateral border of the talus. For trauma imaging, the base of the 5th metatarsal should be seen in profile with the foot in a natural dorsiextended position. In some cases the foot may be flexed to 90 degrees to displace the calcaneus.
    3. Placing the lower leg parallel with the film opens the tibiotalar joint space. It may be necessary to raise the lower leg slightly off the table when the calf muscle is large. The CR enters perpendicular to the tibiotalar joint at the level of the medial malleolus.
    4. An optimal radiographic exposure technique will visualize all surrounding soft tissue, good penetration of the distal tibia/fibula, and show the trabecular bone markings with sharp clear bone margins. Any degree of motion artifact is unacceptable.

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    These two images demonstrate what should be seen on the AP view of the ankle. The CT 3-D volume rendered image on the left shows the bone surface anatomy of the ankle. The white arrows point to the medial mortise joint, which should be projected open on the AP view. The lateral mortis joint is closed on the AP view as the fibula superimposes part of the talus (radiograph on right). The tibiotalar joint should be open, which is related to getting it perpendicular to the CR. Notice that the soft tissue shadows about the malleoli and the proximal foot are included on the radiograph. Radiographic exposure must show these shadows when imaging the ankle because this is where clues pointing to subtle injury are seen.


        The Mediolateral Projection

      1. The mediolateral projection demonstrates the ankle joint, entire calcaneus and talus, and the talocalcaneal (subtalar) and calcaneocuboid joints. The tarsal sinus should be opened.
      2. The true lateral ankle radiograph should demonstrate superimposed talar domes; an opened tibiotalar joint, and the distal fibula superimposed by the posterior one half of the distal tibia. The base of the 5th metatarsal should be visualized within a well-collimated field.
      3. Radiographic exposure technique should show a well-penetrated calcaneus and talus. All surrounding soft tissues must be demonstrated without “burnout,” and the anterior pretalar and posterior pericapsular fat pads demonstrated.
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      These two images show what should be demonstrated on the mediolateral view of the ankle. The 3-D CT volume rendered surface image on the left shows the relationship of the tibia and talus. The radiograph demonstrates the entire talus and trochlea, calcaneus, navicular, cuboid, superimposed cuneiforms, and base of the fifth metatarsal. The soft tissues surrounding the visualized bone are optimally displayed and good bone trabecular pattern and sharp border edges are demonstrated. Notice the posterior malleolus (A) that is often described when there is a trimalleolar fracture. It is a mild roughen area on the posterior aspect of the tibia. The correct relationship of the fibula’s lateral malleolus with the talus is displayed. Notice that it articulates more posteriorly than does the medial malleolus. The subtalar joint (B) is demonstrated opened on both images. The tibiotalar joint (yellow arrowheads) is projected open when the ankle is in a true lateral position. The fat pads of the ankle are easily seen.

        The Ankle Mortise (medial oblique) Projection

      1. Mortise view is taken with the foot/ankle rotated medially 15-20 degrees. The lower leg is placed parallel with the tabletop to open the medial mortise (tibiotalar joint). The foot is dorsiflexed 90 degrees to the lower leg projecting the calcaneus distal to the lateral malleolus. A perpendicular CR enters the ankle at the level of the medial malleolus.
      2. On a properly position medial oblique position the entire ankle mortise should appear open, especially the talofibular joint (lateral mortise) space. The medial mortise is related to how parallel the lower leg is to the image receptor.
      3. The medial oblique view should demonstrate the distal tibia/fibula and proximal talus and their articulations.
      4. Soft tissue and bone detail should be adequate to identify and characterize a fracture, dislocation, or soft tissue injury. Optimally, the radiographic exposure should display no motion on the radiograph, good trabecular marking and sharp bony margins.


      image220
      These two radiographs demonstrate the ankle mortise view of the ankle. The left ankle radiograph is a 15-degree oblique, and the right ankle radiograph is a steeper 20-degree oblique. This view demonstrates the ankle mortise with the lateral mortise (talofibular joint) completely opened and the fibula free of superimposition by the talus and other tarsal bones. The proper amount of obliquity is determined by aligning the intermalleolar line parallel with the image receptor. The tibiotalar portion of the joint is not as opened as is the left one. To open the joint raise the distal leg placing the joint parallel to the CR.

        The External Oblique (Trauma) Projection

      1. The external oblique projection, often called the trauma oblique projection, gives an additional look at the ankle. The view is taken at some institutions to demonstrate the ankle from an alternative perspective.
      2. With this projection the ankle joint is seen and soft tissues along the lateral edge of the fibula. The oblique varies in degrees with the standard being 45 degrees lateral rotation of the ankle/foot.
      3. The diagnostic criteria for this view are not specific, although the distal fibula should be superimposed along its lateral edge with the tibia. The borders of the ankle joint should be demonstrated in profile and well penetrated.
      4. A sponge is usually placed under the heel to raise the ankle joint slightly so that the CR enters the ankle joint perpendicular to it. Alternatively, a slight angle on the x-ray tube may be used when the ankle cannot be raised.
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      These two radiographs of the right and left ankle show the great variations in the amount and purpose for the external oblique view (trauma oblique). Because this view is not a standard view there are no specific guidelines on positioning, except that it is commonly made as a 45-degree oblique. Therefore, we do not make specific diagnostic criteria for this view, but do recommend that the anatomy demonstrated fall within the positioning guidelines for the ankle view and associated visualization of the articulations of the ankle.
      image223
      This radiograph demonstrates the external oblique projection commonly called the trauma oblique. It offers a 45-degree external oblique view of the ankle, which shows it in a different perspective. Notice that this position demonstrates soft tissues on the posterolateral side of the ankle in profile. The fracture lines in the tibia are clearly defined. This projection because of its limited value is not commonly performed, except when a four view trauma ankle series is requested.

      Now that we have discussed the anatomy of the ankle and foot let’s review specific radiographs, which we will critique using the diagnostic criteria for each view.

      Radiograph #113

      image113 This patient underwent surgical repair of distal fibula and tibia fractures. This radiograph was taken to evaluate internal fixation and post surgical bone alignment. Does this radiograph meet the diagnostic criteria for the AP view of the ankle?

      Critique of Radiograph #113

      image113 Bone alignment and integrity of internal fixation is being evaluated. Our focus is on whether this is a well-penetrated properly positioned part. The ankle is properly positioned being fixed within a splint. The required anatomy of the distal leg is demonstrated with good display of surrounding soft tissue detail. All fixation parts are entirely seen with excellent bone, metal, soft tissue contrast. What is really outstanding about this radiograph is that the technologist penetrated the talus without burnout of the soft tissues. This is an excellent radiograph that meets diagnostic criteria!

      Radiograph #114

      image114 This patient presented to a local emergency room with an acute traumatic injury while skiing. Does this horizontal beam projection meet the diagnostic criteria for the mediolateral view of the ankle?

      Critique of Radiograph #114

      image114

      There are extensive injuries of the lower leg and foot that make optimal positioning of the ankle elusive. However, we can see that the required anatomy is demonstrated (entire talus, distal one-fourth of tibia/fibula, and 1 inch of the 5th metatarsal base). There is good bone penetration and soft tissue detail displayed. This appears to be a compound (open) fracture. The ice packs obscures what may be a tract leading from the skin surface to the fracture. Therefore, it is always advisable to remove ice packs and other obstructing dressings. You should not remove a splint, not even a field splint when the patient presents with obvious deformity of the limb. Overall this is a good survey radiograph even though there is some rotation indicated by a closed subtalar joint.

      Radiograph #115

      image115 Consider these trauma radiographs (AP and medial oblique views) of the ankle. Do they meet the diagnostic criteria, and when giving your critique comment about the collimation used seen on this film?

      Critique of Radiograph #115

      image115a

      Great care must be taken when two exposures are made because scatter may cause fog, which reduces subject detail. Also, the part should be aligned with the long axis of viewing for each projection. On the left is the AP view, which is properly positioned, well penetrated, and has great subject detail. The medial/internal oblique view demonstrates the lateral ankle mortise joint opened, and the distal fibula and talus in profile. Both views demonstrate excellent exposure technique selection with good bone and soft tissue detail and contrast. The one point that warrants mention is our obligation to practice ALARA through proper collimation of the part. The area below the white line represents unnecessary patient exposure and adds nothing to the diagnostic value of the radiograph. This area should have been collimated from the field of view. Otherwise, this is a good radiograph.

      Radiograph #116

      image116 The triage notes on this patient indicated a fall that resulted in a painful swollen right ankle injury. The AP view is on the right and medial oblique on the left. Do these radiographs meet the diagnostic criteria for their respective projections?

      Critique of Radiograph #116

      image116

        These radiographs do meet the diagnostic criteria for their respective projections. Both demonstrate the distal third of the leg and the entire talus. All soft tissue structures are seen, and there is good bone penetration on both views. On the left is the medial oblique view showing an accurately positioned ankle mortise with the lateral mortise open and the distal fibula free of superimposition by the talus. The AP view on the right shows the fibula slightly superimposed by the talus and the medial mortise in a normal anatomical position. It is common to put two views on one radiograph as is seen in this example. Notice that good collimation was used and there is minimum scatter beyond the collimated border between the two views. Overall this is a diagnostic radiograph.

      Radiograph #117

      image117 This patient presented to the emergency room of a local hospital with chief complaint of trauma to the ankle. Clinical history included swelling and tenderness over the lateral malleolus. Does this radiograph meet the diagnostic criteria for the AP and medial oblique views of the ankle?

      Critique of Radiograph #117

      image117

      Swelling around the area of the lateral malleolus is noted on this radiograph. There is good balance between bone penetration and soft tissue detail. Because of the clinical history and physical presentation of the patient it is important to demonstrate the ankle mortise and distal fibula free of the talus. The oblique view (left) shows the fibula is superimposed on the heel (calcaneous). This is a positioning error that could have been corrected with proper dorsiflexion of the foot. Pain, swelling, and deformity are reason not to dorsiflex the foot. However, this is a case where we need to slightly flex the foot to clear the fibula from superimposition on the heel. The ankle mortise is properly demonstrated indicating the correct amount of medial rotation of the foot/ankle was achieved. There is a significant amount of image blur seen in the both the AP and oblique views. To reduce patient motion use a sand bag to steady the foot, or tape the extremity in a way that will reduce involuntary motion. This will give the final radiograph good bone trabecular bone detail needed to detect subtle fractures or see soft tissue indicators of underlying ligament injury.

      Radiograph #118

      image118 The clinical history for this exam was “pain, difficulty bearing weight, fourteen weeks post-op ORIF.” Evaluate for bone alignment and healing of fractures. Do these views meet the diagnostic criteria for the ankle?

      Critique of Radiograph #118

      image118

      The diagnostic criteria for the views seen are met. Specifically, the AP medial oblique view (right) shows good spacing between the fibula and talus, and the talus and tibia mortise. The entire fibula and tibial internal fixations are demonstrated in good position. The AP view (left) shows a good anatomical positioning of the ankle. Notice that the entire fixation apparatus is demonstrated on both views and is well penetrated. The technologist did demonstrate good detail around the screws in the fixation since signs of infection or loosening are in question. Soft tissues surrounding the ankle are also properly demonstrated by the exposure technique. Excellent radiograph!

      Radiograph #119

      image119 History for this exam is right ankle trauma with painful swollen ankle. Does this radiograph meet the diagnostic criteria for the AP and medial oblique views of the ankle?

      Critique of Radiograph #119

      image119

      The AP view is seen on the right and the medial oblique view is seen on the left. The foot is in inversion and dorsiflexed. Poor penetration of the distal talus is a result of improper foot positioning. There is good soft tissue detail surrounding the lateral and medial malleoli. As for the oblique (Mortise) view, the fibula is seen free of superimposition on the lateral talus and the ankle mortise is well demonstrated. Like the AP view, the radiographic exposure shows high contrast or poor penetration through the inferior part of the talus. Soft tissue is demonstrated adequately on the oblique view. Either the AP or oblique view should be repeated using more kVp to penetrate the talus, and reposition the foot. Otherwise these are good radiographs.

      Radiograph #120

      image120 AP and lateral views of the left ankle were taken postoperatively in the recovery room. Clinical history, “evaluate internal fixation and bone alignment.” Does this radiograph meet the diagnostic criteria for the AP view?

      Critique of Radiograph #120

      image120

      The ankle is positioned adequately although the lateral talus does not superimpose the fibula. A well-penetrated metallic fixation is entirely demonstrated with good bone detail. Anatomical demonstration of the visualized ankle mortise is properly seen. Overall, this is a well-positioned radiograph displaying good contrast resolution through the plaster splint. This is a great radiograph that meets the diagnostic criteria for the AP ankle view.

      Radiograph #121

      image121 This patient presented to a local emergency room following acute trauma involving the right lower leg. Clinical evaluation revealed deformity of the lower leg and unstable ankle motion. The part was not splinted; however, immediate radiographs of the ankle to include this AP view were taken. Does this radiograph meet the diagnostic criteria for the AP projection; give reasons for why it does or does not?

      Critique of Radiograph #121

      image121

      On an accurately positioned AP ankle view the distal one fourth of the leg, talus, and all surrounding tissues of these structures should be included. In addition, the tibiotalar or medial mortise should be opened on the AP view. However, this patient presents with deformity requiring the technologist to take this projection in the “as is” position. So the main issue with this radiograph is that it is poorly penetrated through the distal tibia/fibula, and talus. This is a very serious type of injury involving the ankle and possibly the talus and other bones of the foot. Therefore, good well-penetrated images are required without exception for interpretation. It is obvious that the extent of injury cannot be assessed from plain films alone, so discuss getting a CT scan with the radiologist before repeating any projections. Axial tomography with coronal and sagittal reconstructions will be needed.

      Radiograph #122

      image122 This radiograph was taken following a surgical placement of an external fixation device. The patient had initial radiographs that showed a comminuted fracture of the distal tibia. The orthopedic surgeon specifically wanted a “true” AP view of the ankle. Does this radiograph meet the diagnostic criteria?

      Critique of Radiograph #122

      image122

      This is an exceptionally well-positioned part that demonstrates a true anatomical AP position. Notice how the ankle joint is demonstrated opened with the lateral and medial mortise in profile. The talus trochlea is positioned in the ankle mortise without rotation. The relationship of the ankle mortise and the fragments of the distal tibia are demonstrated. The radiographic exposure technique shows a well-penetrated talus and distal tibia/fibula. The fragments of the tibial fracture are also well penetrated so that the fracture can be fully characterized. There is great bone detail and soft tissue detail seen in this radiograph. This is a great radiograph that meets the diagnostic criteria for the AP view.

      Radiograph #123

      image123 This radiograph was taken on a patient who was brought to a local emergency room by ambulance following a traumatic injury while skiing. The emergency room physician ordered a four view trauma ankle series. Does this radiograph meet the diagnostic criteria for the AP view of the ankle?

      Critique of Radiograph #123

      image123

      The positioning seen here does not demonstrate the ankle in a true anatomical AP view. Being that the part is not splinted it is difficult to position the ankle without risk of further injury. Also there are complex fractures seen in the distal tibia and fibula and the ankle joint may also be dislocated. The heel is projected over the lateral edge of the tibia indicating the part is laterally rotated. This is a complex fracture type and a true AP is necessary. The likelihood that a CT or MRI scan of the part will be performed is high, therefore, I would suggest completing the study and consulting with the radiologist or emergency room physician about further imaging. Manipulating the foot or ankle too align the part may be contraindicated and could do further harm. The radiographic exposure technique is adequate for soft tissue; however, bone penetration, bone trabecular pattern, and cortical bone edge sharpness is lacking. This is due in part to exposure technique and in part to patient motion. Increasing the overall kVp at least 15% and making appropriate changes in mA to reduce motion will greatly improve this radiograph.

      Radiograph #124

      image124 The cause of this injury was a twisted ankle while playing volleyball. This AP view is part of a 3 view series. Does this radiograph meet the diagnostic criteria, why or why not?

      Critique of Radiograph #124

      image124

      A criterion for all projections of the ankle is that all of the anatomy must be demonstrated. For the AP view this would include the distal one fourth of the tibia and fibula, and the entire talus. Clearly, the medial malleolus is clipped and perhaps part of the distal talus as well. The cause is not over collimation because the part is masked by a black edge. This can happen with digital imaging when the collimation mask is set for a black background. Removing this feature will allow the entire medial edge to be seen and a clear edge demarcating the collimated border. As for the radiographic exposure technique there is good soft tissue detail seen in the visualized portion of the anatomy. Notice that the talus however, is not well penetrated. It is important to penetrate the talus, as it is part of the diagnostic criteria for the ankle. Because the talus is partially dislocated and there may be some ligament damage as well. This radiograph must be repeated to include all of the required anatomy and to better penetrate the talus.

      Radiograph #125

      image125 Consider these two views of the ankle, on the left is the AP view and the medial oblique view is on the right. Do these two views meet the diagnostic criteria for their respective views?

      Critique of Radiograph #125

      image125

      The ankle is positioned correctly for the AP view showing slight overlap of the tibia and fibula. The medial mortise is opened and the fibula is slightly superimposes the lateral mortise. Bone penetration is adequate for diagnosis. The oblique view shows great penetration of the distal tibia, fibula, and talus. The fibula is projected free of superimposition by the tibia or talus, and the lateral ankle mortise is projected opened. Notice that the source-to-image distance (SID) decreased for the oblique view (slightly magnified). Also, a bit more of the medial soft tissue of the ankle could have been included. These are good radiographs of the ankle that meet the diagnostic criteria for their respective views.

      Radiograph #126

      image126 This trauma patient was brought to the emergency room by ambulance with the leg in a splint. The oblique and AP views are included on one film. Discuss whether or not each view meets their respective diagnostic criteria?

      Critique of Radiograph #126

      image126

      It is obvious that the site of fracture of the fibula is not entirely demonstrated. For the AP and oblique views the distal one fourth of the tibia/fibula must be included for all trauma views. Failure to demonstrate the fracture components of the fibula is the primary reason for the radiographer to take further action. The radiographic exposure technique is adequate for the oblique view, but shows underpenetrated on the AP view. So the best course of action is for the technologist to consult with the ordering physician about getting entire tibia/fibula views. Because the fracture may involve a larger area of the leg than is demonstrated by the ankle views this is the best way to serve the patient. When the AP tibia/fibula view is taken increase the kVp to penetrate the talus. The ordering physician may also choose to get a CT scan because of the complexity of the fractures seen.

      Radiograph #127

      image127 This mediolateral view of the ankle was taken as part of a 4 view trauma series. Patient history included trauma with clinical signs of swelling and pain. Does this radiograph meet the diagnostic criteria for the lateral view of the ankle?

      Critique of Radiograph #127

      image127

      The diagnostic criteria for the mediolateral view states that the entire talus and calcaneus should be demonstrated and their articulations with adjacent tarsal bones. The upper arch of the tibiotalar joint should be presented open with a uniformed joint space. The edges of the tibia and trochlea of the talus should be sharp and clear throughout the joint articulation. The lateral malleolus and distal fibula should be superimposed over the posterior half of the talus, and the fibula superimposes the posterior half of the tibia. These diagnostic criteria have been met on this radiograph. There is optimal radiographic exposure as the trabecular markings of the tibia, talus, calcaneus, and visualized navicular bones are clear and sharp. The distal fibula is demonstrated through a well-penetrated talus and soft tissues surrounding the ankle anteriorly and posteriorly is clearly defined. Excellent radiograph!

      Radiograph #128

      image128 This is a post reduction view of the right ankle performed in the emergency room. The orthopedic surgeon requested the AP and lateral views. Does this radiograph meet the diagnostic criteria for the mediolateral view, why or why not?

      Critique of Radiograph #128

      image128

      It can be difficult to provide optimal bone detail when imaged through a plaster cast. For this reason a fiberglass cast is often used when bone detail is desired. A splint or cast can limit the technologist ability to position the part, as position is in part determined by the cast limitations. The ankle is not in a true lateral mainly because the foot is dorsiflexed. This cannot be corrected because the foot is in a cast. The medial and lateral talar domes are superimposed. This is an indicator that the ankle is in a true lateral position. Selecting the correct exposure technique is more difficult for a wet cast vs. a dry cast or even fiberglass material. This appears to be a wet cast, which degrades the quality of the image unless the exposure technique is optimally adjusted. Generally, an increase in the kVp of at least 20% is required for a wet cast.

      Radiograph #129

      image129 Give your critique of this mediolateral ankle radiograph taken for trauma. Does the positioning of the part and radiographic exposure meet the diagnostic criteria?

      Critique of Radiograph #129

      image129

      This radiograph demonstrates the entire talus, cuboid, navicular, calcaneus, and some of the tarsal bones. The ankle joint is demonstrated with the medial talar dome slightly anterior to the lateral dome. The cause is that the foot is inverted rather than being placed parallel to the image receptor. Generally, about 1 inch of the cuboid is demonstrated free of the navicular bone. The entire cuboid and base of the 5th metatarsal is seen free of superimposition by the other metatarsal bones. This radiograph does not need to be repeated, which is in keeping with ALARA. It should be noted that to correct the positioning of the ankle one should elevate the forefoot and depress the heel to align the lateral foot surface parallel with the cassette. Radiographic exposure demonstrates sharp clear trabecular markings throughout visualized bone.

      Radiograph #130

      image130 This patient’s chief complaint was “unable to walk on ankle” following trauma. The physician requested that an AP, oblique, and lateral views of the ankle be taken. Does this radiograph meet the diagnostic criteria for the mediolateral ankle view?

      Critique of Radiograph #130

      image130

      The required anatomy is demonstrated on this radiograph. The ankle joint is projected opened with the fibula superimposed along the posterior third of the talus. The medial and lateral talar domes are superimposed and the subtalar joint is demonstrated opened. The radiographic exposure shows sub optimal trabecular bone detail, but distinct cortical bone detail. The trabecular markings are blurred due to involuntary patient motion. This radiograph should be repeated because of the lack of bone detail due to motion artifact. A minor point to be mentioned is that too much of the proximal leg is included. However, to be fair to the technologist it may be because the physician requested to see this area. Otherwise, collimate to the distal one fourth of the leg for all ankle views.

      Radiograph #131

      image131 This patient hopped into a local emergency room complaining of “a twisted” ankle. This radiograph is part of a 4 view trauma series. Does it meet the diagnostic criteria for the mediolateral view?

      Critique of Radiograph #131

      image131

      Although this is not an optimal radiograph, it does not need to be repeated. The main reason this is not an optimal radiograph is positioning errors. Notice that the lateral surface of the foot is not parallel with the cassette and the foot is not dorsiflexed. This has placed the fibula in the middle third of the talus rather than towards the posterior part of the talus. When properly positioned the fibula should be superimposed along the posterior edge of the talus. Overall this is a good radiograph that meets the diagnostic criteria for the mediolateral projection of the ankle, though it is not optimal.

      Radiograph #132

      image132 This radiograph was taken after a plaster cast was placed to support a fracture of the distal tibia. The requesting physician wanted to “check alignment of the distal leg.” Does this radiograph meet the diagnostic criteria for the mediolateral ankle view?

      Critique of Radiograph #132

      image132

      The leg is properly positioned as seen through the splint. The ankle joint is opened and the talar domes are superimposed. If you look closely along the anterior and posterior edges of the tibia you can see the break in the cortex at the fracture sites. Also the fracture through the posterior and inferior parts of the tibia can also be clearly seen. This is a good well-positioned radiograph of the ankle and distal leg. The radiographic technique shows good bone detail and relatively good soft tissue contrast through the splint. It is important to remember that when a fiberglass splint is used the exposure technique is not increased. However, when a wet plaster splint is used at least a 20% increase in the mAs is required and a 15% increase in the kVp. This is a good optimal radiograph.

      Radiograph #133

      image133 The clinical history is “stepped off curb, twisted ankle, evaluate for fracture.” The emergency room physician requested a 4 view trauma ankle series. Do these two radiographic images meet the respective diagnostic criteria for the AP external oblique, and mediolateral views?

      Critique of Radiograph #133

      image133

      The AP external oblique view on the right shows the foot and ankle in external rotation. The standards for this view are loose as it is mainly used to show the ankle from another position. Therefore, this view is less critical to diagnosis and critique. On the-other-hand the lateral view on the left does not demonstrate all of the required anatomy. For example, the calcaneus along with its surrounding soft tissues is not entirely demonstrated. The medial and lateral talar domes are not superimposed. The lateral talar dome is demonstrated anterior and proximal to the medial talar dome. The lateral surface of the foot must be placed parallel to the image receptor and the lower leg positioned parallel to the tabletop. Reasons the lateral view should be repeated include: 1) the talar domes are not superimposed, 2) the subtalar joint and sinus tarsi is not opened, 3) the base of 5th metatarsal is not seen, and 4) entire calcaneus is not demonstrated.

      Radiograph #134

      image134 These two views, the lateral on the left and the external oblique on the right were taken because of an injury to the ankle. The patient was playing baseball and hurt the ankle during a slide into third base. Do these views meet the diagnostic criteria for their respective views?

      Critique of Radiograph #134

      image14

      It is quite common to place two views of the ankle side by side on the radiograph as is seen here. The mediolateral view shows relatively good positioning with the fibula slightly superimposed on the posterior tibia. The subtalar joint is seen opened and a proper amount of the cuboid and navicular bones seen. Trabecular markings are good, and clear sharp cortical bone margins are displayed. The external oblique has limited value and therefore undefined diagnostic criteria. Overall, the oblique view shows the ankle joint, medial malleolus, and parts of the distal tibial in profile. The lateral malleolus and surrounding soft tissues are also noted. Slightly less rotation of the ankle would demonstrate more of the lateral tissues if this area were in question. Overall, these are good diagnostic radiographs of the ankle.

      Radiograph #135

      image135 This was a trauma patient whose chief complaint was pain along the lateral malleolus. Clinical evaluation confirmed swelling and discoloration along the left surface of the foot and lateral malleolus. Does this radiograph meet the diagnostic criteria for the mediolateral view, why or why not?

      Critique of Radiograph #135

      image135

      In order to properly evaluate the lateral malleolus the ankle must be in a true lateral. A true lateral can be determined by looking at the talar domes and the tibiotalar joint. It is difficult to determine if the medial and lateral talar domes are superimposed on this radiograph, but certainly, the tibiotalar joint is not opened along its course from anterior to posterior. Also, the fibula is projected much too posterior relative to the tibia. On an accurately positioned mediolateral view the distal fibula is superimposed on the posterior one half of the tibia. Extending the patient’s leg so that it is parallel with the tabletop will help correct the faulty positioning. The foot should be dorsiflexed, not extended as is seen on this radiograph and the lateral surface of the foot parallel with the cassette. These changes will place the ankle in a true lateral position. This radiograph does demonstrate the required anatomy (distal one fourth of the tibia/fibula, entire talus, calcaneus, cuboid, and part of the base of the 5th metatarsal). Exposure demonstrates good bone and soft tissue detail. Repeat because of positioning errors.

      Radiograph #136

      image136 This patient presented to a local emergency room with a chief complaint of ankle pain. Clinical history included sports injury from twisting of the ankle. Patient presented with swelling and ankle pain. Does this radiograph meet the diagnostic criteria for the mediolateral ankle view?

      Critique of Radiograph #136

      image136

      This is a classical example of the type of radiograph that may be presented for interpretation when the diagnostic criteria are not used. The anatomical ankle is demonstrated (distal tibia, distal fibula, and talus); however the radiographic ankle is not. Radiographic criterion for anatomy to be demonstrated is the entire calcaneus, entire cuboid with three-quarters free of the navicular, and the entire base of the fifth metatarsal. The other point is that the radiographic exposure technique shows high contrast with underpenetrated talus. Notice that the distal fibula although seen through the talus is also not well penetrated. The soft tissues surrounding the ankle are burned out so that the anterior and posterior precapsular fat pads cannot be properly evaluated. This radiograph should be repeated. Decrease the mAs by half using the 50/15 rule and increase the kVp by 15 percent. This will better penetrate the talar domes and bring out the soft tissue detail not seen on this radiograph.

      Radiograph #137

      image137 As part of a four view trauma series of the ankle this external oblique view was taken. Does this radiograph meet the diagnostic criteria for the ankle, why or why not?

      Critique of Radiograph #137

      image137

      This external oblique view (trauma oblique) of the ankle is taken to provide a different look at the ankle, which proved beneficial for this comminuted fracture. The external oblique does not have a strict diagnostic criterion, but usually 15 to 20 degrees external rotation is adequate. This radiograph shows the bone fragments in profile along with the associated soft tissue swelling. As with any radiograph it is important that the part be well penetrated. In this case the distal fibula and talus is poorly penetrated which decreased the value of this view. Because the external oblique is an optional projection, and we can see the fragments nicely, repeating this projection is not advisable.

      Radiograph #138

      image138 Consider this radiograph that shows obvious traumatic injury to the ankle. In your critique discuss whether or not the part is properly positioned, and state whether or not it should be repeated.

      Critique of Radiograph #138

      image138

      This is an example of a radiograph that does not meet the diagnostic criteria, but may not necessarily need to be repeated. Clearly, the lateral talar dome is anterior and proximal to the medial talar dome. The talar domes should be superimposed when the ankle is in a true lateral. The fibula should be superimposed on the posterior half of the tibia, which on this radiograph is seen along the anterior half of the tibia. As a result the tibiotalar and subtalar joints are not demonstrated opened. This clearly is not a true lateral view of the ankle. If this projection is taken as a horizontal beam lateral, then the lateral surface of the foot should be positioned parallel with the cassette. Also include the base of the fifth metatarsal and the cuboid. A CT scan is often performed when a comminuted fracture involves the joint. Therefore, repeating this radiograph is not necessary pending CT scan.

      Radiograph #139

      image139 This patient suffered a traumatic event and presented to a local emergency room with a swollen ankle, pain, and unable to bear weight. Does this radiograph meet the diagnostic criteria for the mediolateral ankle view?

      Critique of Radiograph #139

      image139

      Positioning errors on this radiograph are obvious. Although the talar domes are superimposed, the fibula is not projected to the distal half of the tibia. Furthermore, the medial malleolus is seen along the posterior edge of the talus and partially superimposed on the calcaneus. The subtalar joint is closed. Clearly, the foot is slightly inverted and not parallel to the image receptor. The radiographic exposure adequately demonstrates soft tissues, however, the distal leg and talus are not well penetrated. This radiograph should be repeated correcting the positioning errors. Also the exposure technique should be changed, specifically, decrease the mAs and increase the kVp to penetrate the ankle joint.

      Radiograph #140

      image140 When considering your critique of this radiograph comment on the placement of the AP and lateral views anatomically opposite. Also comment on the poor use of collimation seen here, and state whether or not these views meet their respective diagnostic criteria.

      Critique of Radiograph #140

      image140

      When taking two projections on the same cassette the cassette should be turned so that the part is facing the same direction for both views. This makes it easier to diagnose and compare structures. Collimation in keeping with ALARA is recommended for all uses of ionizing radiation. That’s why only the distal one fourth of the leg is demonstrated on ankle views. As for positioning, the lateral view (right) meets the diagnostic criteria, but the AP view (left) does not. Notice the fibula is entirely superimposed on the tibia. This is not a true AP projection because the leg is externally rotated. As a matter of professionalism, keep in mind that when you put two views on one radiograph strive for excellence. Notice that the sub optimal radiograph will be seen by all views along with the repeated radiograph. So take your time, especially with pediatric patients to be sure you are getting the best image possible with the first exposure.

      Radiograph #141

      image141 Name this radiographic projection and discuss the diagnostic value of this view.

      Critique of Radiograph #141

      image141

      This is a lateral stress view of the ankle. Sometimes the orthopedist will stress the ankle or request the technologist perform stress views. Stress views include inversion (or talar tilt) and eversion. Variables in determining the reliability of these tests include the degree of patient pain (local anesthesia may be required), relaxation and cooperation, the amount of force used, the angle of ankle flexion, and the amount of laxity in the uninvolved side. The ankle held in the AP neutral position or in slight plantarflexion, with an inversion stress applied to the foot. The angle to be measured is formed by a line parallel to the subchondral bone of the distal tibia and proximal talus. The assumption behind this test is that the contralateral side of the ankle is without injury and is normal. The test is positive when the injured ankle has a stressed angle of 5-10 degrees greater than the uninjured ankle. This is reliable for a torn ATFL and CFL in 97% of cases. No critique of this radiograph is needed.

      Radiograph #142

      image142

      This is also a stress view of the ankle using a calibrated mechanical device to position the ankle in proper dorsiflexion and apply the prescribed amount of stress to the ankle. This is a good radiograph because it is labeled and the direction of stress indicated. The orthopedic physician prescribes the amount of stress and need not be present when a pressure meter apparatus like the one on this radiograph is used. This should only be performed by those trained in using these devices.

      Radiograph #143

      image143

      This is also a stress view of the ankle with stress being applied from the lateral side to evaluate the medial mortise. This too is a great stress view showing good bone penetration and sharp bone edges. The ankle mortise is well penetrated so that the diagnosis of the tibiotalar joint space can be evaluated. This radiograph is included for your information and not for critique. Proper positioning and amount of stress is applied using a stress apparatus. Stress is applied above the ankle joint.

      Summary: Critique of Ankle Views

      • The AP projection:
        1. Should demonstrate one fourth of the distal tibia and fibula, and the entire talus.
        2. Mortise view (15-20 degree medial oblique) should demonstrate the ankle mortise and the distal tip of the fibula free of superimposition by the talus and other bones of the foot. To accomplish a freed distal fibula slight dorsiflexion of the foot may be necessary.
        3. The medial and upper portion of the ankle mortise joint should appear open, but the lateral mortise closed due to a superimposed distal fibula on the lateral edge of the talus. The base of the 5th metatarsal should be seen in profile with the foot in a natural dorsiextended position for trauma imaging.
        4. An optimal radiographic exposure technique will visualize all surrounding soft tissue, good penetration of the distal tibia/fibula, and show the trabecular bone markings with sharp clear bone margins void of motion artifact.
      • Medial and lateral oblique views:
        1. Mortise view (15-20 degree medial oblique) should demonstrate the ankle mortise and the distal tip of the fibula free of superimposition by the tibia or bones of foot.
        2. On a properly position medial oblique position the entire ankle mortise should appear open, especially the lateral mortise of the talofibular joint. This is a 45-degree oblique not the ankle mortise view.
        3. Soft tissue and bone detail should be adequate to identify and characterize a fracture, dislocation, or soft tissue injury. Optimally, the radiographic exposure should display no motion on the radiograph, good trabecular marking and sharp bony margins.
        4. The lateral oblique (trauma oblique) shows the ankle in external rotation. Gives a good face view of the tibia and medial malleolus. Usually between 25 and 45 degrees of external rotation is sufficient. The lower leg is kept parallel with the image receptor.
      • Lateral (mediolateral) view
        1. Should demonstrate the distal tibia and fibula, the talus, calcaneus, sinus tarsi, and navicular bone should be demonstrated in their entirety. The articulations of these bones with adjacent tarsal bones should also be demonstrated.
        2. When in a true lateral, the distal fibula is superimposed on the posterior half of the distal tibia.
        3. The talocalcaneal (subtalar) and tarsal sinus, and calcaneocuboid joints should be demonstrated showing good open joint spaces. The talar domes should be superimposed so that the tibiotalar joint is seen opened throughout its course.
        4. Radiographic exposure technique should show optimal penetration of the calcaneus and talus. All surrounding soft tissues must be demonstrated without “burnout,” and the anterior pretalar and posterior pericapsular fat pads demonstrated.
      Always ask, "Have I met the diagnostic criteria for this view?”
      Diagnostic Criteria for Imaging the Foot:


        Orthopedic injuries involving the foot are frequently seen in emergency rooms. Traumatic foot injuries can present with neurovascular compromise. Furthermore, delayed diagnosis and treatment is associated with long-term increased morbidity. Diagnostic imaging plays a key role in reducing long-term morbidity. Therefore, when requested to image the foot three standard projections are generally taken for trauma or general diagnostic imaging of the foot. Proper imaging of the foot is necessary since about 10% of all fractures occur in the foot. The standard AP view superimposes the second through fifth metatarsal bases, and visualization of the third cuneiform and cuboid bones are somewhat difficult to demonstrate. The medial oblique projection provides a clearer visualization of these areas and plainly shows the articulations of the cuboid and intermetatarsal joints spaces. Follow-up radiograph to check the progress of orthopedic repair must meet specific diagnostic criteria to make evaluation complete. Standard radiographs of the foot consist of AP, medial oblique and lateral views of the foot and can be taken with or without weight bearing depending on the diagnostic evaluation sought. Each of these views has their diagnostic criteria, which are discussed below:

          The Foot AP (Dorsoplantar) Projection

        1. The AP foot view should demonstrate all bones of the foot including the phalanges, metatarsals, tarsals, proximal calcaneus, talar neck, and all surrounding soft tissues.
        2. When properly positioned the following articulations of the foot should be open: tarsometatarsal joints, navicular-cuneiform joint, talo-navicular joint, and the space between the medial and intermediate cuneiforms. To properly demonstrate these joints the central ray enters the foot at the base of the metatarsals. When the foot is properly positioned without medial or lateral rotation the joint space between the medial and intermediate cuneiforms is demonstrated. The talus only partially superimposes the navicular bone demonstrating about 2 cm of the navicular free of superimposition.
        3. Radiographic exposure should display optimum bone density and contrast with sharp border detail. Trabecular markings of the distal phalanges and tarsal bones should be apparent. The radiograph should be free of motion artifact.


        image224


        This weight-bearing (WB) AP projection of the foot demonstrates the required anatomy to be demonstrated on the AP view. In the absence of trauma, weight-bearing (standing views) are taken when requested. Demonstrated in proper anatomical position are: the phalanges, metatarsals, and tarsal bones. Notice the space between the medial and intermediate cuneiforms (yellow arrowhead). The articulation between the talus and navicular bones (white arrow) is better demonstrated on the upright view than on the supine view. This is because the foot is not extended (plantar flexed) on the supine view sufficiently to demonstrate more of the talus.


          AP Oblique Projection-Medial Rotation

        1. The entire foot is demonstrated from the distal phalanges to the posterior calcaneus and proximal talus, and all surrounding soft tissues of the foot.
        2. The distal ends of the third through 5th metatarsals should be completely free of superimposition. The base of the metatarsals may be slightly superimposed; however, the base of the 5th metatarsal should be completely free and well visualized.
        3. The joint spaces surrounding the cuboid are opened when the foot is properly rotated 40-45 degrees medially. When the foot is not properly rotated the cuneiform-cuboid articulation will be closed. Keep in mind that a high longitudinal arch will require a near 45-degree oblique and a low longitudinal arch requires much less rotation of near 30 degrees.
        4. Radiographic exposure is optimal when the tarsals, metatarsals, and phalanges are demonstrated with good density and contrast, good trabecular markings seen and sharp cortical borders. All surrounding soft tissues should be visualized without “burn out.”


        image225


        The radiograph of the right foot on the left demonstrates the medial oblique projection taken with the patient supine. Notice the joint spaces between the metatarsal bases are closed. Likewise, the cuboid-cuneiform intertarsal joint space is closed. This indicates there is a high longitudinal arch and the part should be rotated 45 degrees medially. The standing weight-bearing radiograph of the right foot demonstrates the medial oblique taken with the CR angled medially 30 degrees across the long axis of the metatarsals. Notice that all articulations of the cuboid are opened and the second through 5th metatarsal bases are displayed without superimposition. The talo-navicular joint and sinus tarsi are well demonstrated.


          Lateral (Mediolateral) Foot Projection

        1. Radiographs may be taken supine or erect weight bearing. On an accurately positioned mediolateral foot radiograph the phalanges, metatarsals, tarsals, and at least 1 inch of the distal leg and all surrounding soft tissues are demonstrated.
        2. The ankle should be in a true lateral with the talar domes superimposed and the fibula partially superimposed by the posterior half of the distal tibia.
        3. The calcaneus is seen in profile with the subtalar and talo-navicular joints opened.
        4. Base of the 5th metatarsal is demonstrated in profile. The articulation of the cuboid and calcaneus is well demonstrated with at least 1 inch of the cuboid distal to the navicular bone.
        5. Standing views are needed to demonstrate the medial and/or lateral longitudinal arches.
        6. Optimal radiographic exposure demonstrates good trabecular bone detail and sharp bone edges along cortical bone. All surrounding soft tissue must be visualized along with the posterior pericapsular and anterior pretalar fat pads.


        image226


        This recumbent right mediolateral view demonstrates the proper positioning and radiographic exposure for optimum diagnostic evaluation of the foot. Notice that the ankle is in a true lateral with the fibula superimposed by the posterior half of the tibia. The talar domes are also superimposed and the tibiotalar joint is opened. Only a small portion of the cuboid is superimposed by the cuneiform and the base of the 5th metatarsal is profiled.


        image227


        This weight-bearing mediolateral view demonstrates the required anatomy of the foot. Standing views are sometimes requested to evaluate the longitudinal and transverse arches of the foot, or to evaluate the alignment of healing fractures. The presentation of the required anatomy is the same as for the recumbent view. The talar domes are superimposed and the cuboid seen slightly superimposed by the navicular bone. Notice that the base of the metatarsal is free of superimposition and the longitudinal arch visualized.


        Radiograph #144

        image144 This patient’s chief complaint was chronic foot pain when walking, and history of flatfoot. The ordering physician requested AP, oblique, and a standing lateral views of the foot. Does this radiograph meet the diagnostic criteria for the AP view?

        Critique of Radiograph #144

        image144a

        The diagnostic standards require that the phalanges, metatarsals, and tarsal bones be included within the collimated field. The navicular-cuneiform joint is seen opened, and the joint space between the medial and intermediate cuneiforms is seen. A good portion of the calcaneus is demonstrated without superimposition by the talus. The talo-navicular articulation (arrow) is well penetrated by the x-ray beam. Thus the foot is correctly positioned and the right amount of cephalic angulation of the tube has been applied. It is recommended that good bone penetration be displayed along with sharp bone detail. Decrease the kVp 15% with appropriate increase in mAs will achieve this. Overall, this is a good radiograph that does not need to be repeated.

        Radiograph #145

        image145 Give your critique of this lateral foot projection. Explain why or why it does not meet the diagnostic criteria in your critique.

        Critique of Radiograph #145

        image145

        The mediolateral foot projection should demonstrate the entire foot including the phalanges, metatarsals, tarsals (with good bone detail in the talus and calcaneus). At least one inch of the distal leg and all surrounding soft tissues of the foot and ankle should be demonstrated. A true lateral is achieved when the talar domes are superimposed, the tibiotalar joint space opened, and the fibula superimposing the posterior half of the tibia. Good bone penetration is seen without “burn out” of the toes. The major reason this radiograph should be repeated is patient motion that has degraded subject detail. Notice how the trabecular bone markings, especially in the calcaneus are not clear and sharp. Also, the cortical bone edges appear blurred. Decrease the exposure time to correct motion artifact.

        Radiograph #146

        image146 This is a weight-bearing lateral view of the foot. What are some of the indicators that the foot is in a true lateral, and tell whether or not this radiograph meets the diagnostic criteria for the lateral view?

        Critique of Radiograph #146

        image146

        This weight-bearing lateral view of the foot demonstrated the required anatomical structures of the foot. The talar domes should be superimposed to accurately measure the height of the foot arch. This radiograph demonstrates the talus in a true lateral projection. The cuboid is projected distal to its normal relationship with the navicular bone indicating a fallen longitudinal arch. The radiographic exposure shows good penetration of all bones of the foot. The tarsal and metatarsal joint articulations are well penetrated. This is a good radiograph of the foot that meets the diagnostic criteria for the lateral foot view.

        Radiograph #147

        image147 This patient presented to a local emergency room with a chief complaint of trauma involving the lateral side of the foot. Clinical evaluation revealed inability to bear weight. The emergency room physician requested this radiograph as part of a 3 view trauma foot series. Does this medial oblique view meet the diagnostic criteria?

        Critique of Radiograph #147

        image147 This is a great radiograph in terms of radiographic exposure; however it does not include all of the required anatomy for the oblique view. Although the lateral side of the foot is injured by patient history, the technologist must image the entire foot. It is required that the entire calcaneus, talus, and talo-navicular articulation be demonstrated. An acute fracture involving the base of the 5th metatarsal is noted. However, a positive finding on the lateral side of the foot does not negate the need to meet all components of the diagnostic criteria. The foot is properly positioned demonstrating open articulations on all sides of the cuboid. Nevertheless, this radiograph should be repeated to include all required anatomy. While soft tissue detail is optimal on this radiograph, some may have been omitted on the lateral edge of the 5th distal phalanx. So include all soft tissue both medially and laterally on the repeated projection.

        Radiograph #148

        image148
        Critique of Radiograph #148

        image148

        The foot is properly positioning and all required bone and soft tissue displayed. Clearly, the technologist wanted to penetrate the tarsal bones without burning out the toes. To do this a low contrast exposure was used. This resulted in loss of subject detail needed to provide good bone detail. Using a sufficient kVp to penetrate the part and adjusting the mAs to bring out subject detail is the best approach. Notice the background density shows little blackness. This is a primary indicator there is insufficient mAs. To maintain the overall quality of the radiograph increase the mAs and decrease the kVp using the 50/15 rule. This radiograph should be repeated reducing the kVp by 15 or possibly 30 percent with a concomitant increase in the mAs to make this a great radiograph.

        Radiograph #149

        image149 Given a patient history of trauma, discuss the exposure technique, positioning, and whether or not the required anatomy is presented according to the diagnostic criteria.

        Critique of Radiograph #149

        image149

        This is an example of an excellently positioned mediolateral foot radiograph. The technologist used the correct amount of rotation of the foot based on the height of the longitudinal arch to achieve this presentation. Notice that the joints on all sides of the cuboid are demonstrated opened, and the second through fifth metatarsal bases are free of superimposition. The phalanges are displayed in a way that presents minimal overlap of the interphalangeal joints. The entire talus and cuboid are seen, which is especially important when imaging the entire foot. As for the radiographic exposure technique, surrounding soft tissues are optimally displayed. There is good bone displaying trabecular markings and sharp bone borders. This is an excellent radiograph!

        Radiograph #150

        image150 This radiograph was taken on a patient who was referred to an orthopedist because of chronic foot pain. The physician requested that the study of the foot be performed standing. Does this mediolateral view meet the diagnostic criteria for the foot?

        Critique of Radiograph #150

        image150

        When requested, weight-bearing views of the foot are commonly performed in most radiology departments. The same diagnostic criteria must be met with weight-bearing views as for non weight-bearing views. All of the required anatomy is presented on this radiograph. The foot is parallel to the image receptor, which projects the foot in a true lateral with the talar domes superimposed and the tibiotalar joint open. There is good balance between bone and soft tissue detail. This is a great radiograph that meets the diagnostic criteria for the upright mediolateral foot.

        Radiograph #151

        image151 This radiograph was taken on a patient with deformities of the upper and lower extremities. The technologist attempted placing the patient in a true lateral and got this projection. Does this mediolateral view meet the diagnostic criteria?

        Critique of Radiograph #151

        image151

        Sometimes getting the correct anatomical position can be challenging. Even routine positioning can be a challenge with disorders like cub-foot, inversion and eversion of the and so forth. Without being present to see the patient’s presentation it is easier to say that this is an unacceptable radiograph, and it really is. The foot is definitely not in a true lateral, which takes away from its diagnostic value. The lateral surface of the foot must be placed parallel with the cassette and the central ray directed perpendicular to the foot. Proper rotation of the foot will place the fibula in the posterior half of the tibia and open the ankle joint. Angling the cassette to place the foot parallel is also an option. This projection must be repeated to correct the positioning seen here. The radiographic exposure seems adequate.

        Radiograph #152

        image152 Generally the AP and oblique views of the foot are taken side by side as seen here. These views are part of a 3 view trauma series that includes a lateral view. The area of interest was not specified. Do these views meet the diagnostic criteria for their respective views?

        Critique of Radiograph #152

        image152

        Half of the cassette is usually blocked off with a lead shield for each view to prevent scatter from fogging the images. Close collimation of the oblique view (left) resulted in some soft tissue being omitted near the 1st distal phalanx and along the lateral border of the 5th digit. All bone anatomy is included on both views. The entire calcaneus and talus is demonstrated on both views. The foot is properly rotated opening the cuboid articulations and projecting the bases of metatarsals 2 through 5 are seen free of superimposition. The AP view on the right demonstrates all bone and soft tissue anatomy in proper anatomical presentation. Both views provide good bone and soft tissue detail. These radiographs of the foot meet their diagnostic criteria.

        Radiograph #153

        image158 This patient was brought to a local emergency room with an acute gunshot injury to the distal right foot. The ordering physician specifically requested to see bone and soft tissue detail of the phalanges. Does this radiograph meet the diagnostic criteria for the oblique foot view?

        Critique of Radiograph #153

        image158

        It is important that good bone and soft tissue detail be displayed on any radiograph. The soft tissues of the foot, especially around the phalanges show good detail. The bony elements show good subject contrast, excellent trabecular pattern, and the cortical margins are sharp. This is a great radiograph because the technologist provided good penetration of the tarsal and metatarsals. The proximal foot was not in question; however, the navicular and cuboid bones could be better penetrated. The technologist has demonstrated the required anatomy in proper anatomical representation for this medial oblique view. Overall, this is a diagnostic radiograph that meets the diagnostic criteria for the medial oblique foot view.

        Radiograph #154

        image154 This patient was brought to a local emergency room following a motorcycle accident in which there was multi-system trauma. The foot was obviously deformed due to crush injury on clinical examination. Does this radiograph meet the diagnostic criteria for the medial oblique view?

        Critique of Radiograph #154

        image154

        The required anatomy is presented in its correct anatomical relationships. The cuboid is properly demonstrated with all articulations opened. Likewise the bases of metatarsals 3 through 5 are displayed free of superimposition. The phalanges and metatarsals are seen without “burnout”. Unfortunately the cuneiforms, navicular, talus, and calcaneus are underpenetrated. The exposure technique shows high contrast, which resulted in underpenetration of the talus, calcaneus, and distal leg. An adjustment of at least 15 percent increase in kVp will be required to penetrate the talus. Because there are fractures or dislocations in the forefoot it is important to see this area in great detail. An optimal exposure will demonstrate a well-penetrated talus and calcaneus without “burnout” of the phalanges.

        Radiograph #155

        image153 An orthopedic surgeon requested standing views of the foot on this patient. It was requested that a lateral oblique be taken of the entire foot. What does the lateral oblique view demonstrate, and does this radiograph meet diagnostic standards?

        Radiograph #155

        image153

        Diagnostic criteria for the lateral oblique view were not discussed previously; however, it is covered here because this projection is commonly made in some orthopedic clinics. The lateral oblique is made with the foot rotated laterally 30 degrees or less. This is because a 45-degree oblique would be excessive given the natural curvature of the longitudinal. When the lateral oblique is performed weight-bearing the vertical beam is angled across the longitudinal axis of the foot 30-degrees. The purpose for this projection is to demonstrate the space between the 1st and 2nd metatarsals and between the 1st and 2nd cuneiforms. It also best demonstrates the navicular and the talo-navicular articulation when properly exposed. This radiograph demonstrates the lateral oblique structures but is underpenetrated through the navicular and talus. The tube angle is greater than 30 degrees, which has resulted in the closure of the first and second inter-cuneiform joint.

        Summary of the AP, Mediolateral, and Lateral Foot Views

        • The Foot AP (Dorsoplantar) Projection
          1. The entire foot is demonstrated to including the phalanges, metatarsals, tarsals, proximal calcaneus, talar neck, and all surrounding soft tissues.
          2. The tarsometatarsal joints, navicular-cuneiform joint, talo-navicular joint, and the space between the medial and intermediate cuneiforms are demonstrated. In addition, an open joint space between the medial and intermediate cuneiforms is seen. Approximately 2 cm of the navicular is demonstrated free of the talus.
          3. Radiographic exposure should display optimum bone density and contrast with sharp borders and trabecular markings in the tarsals and phalanges. The image should be free of motion artifact.
        • AP Oblique Projection-Medial Rotation
          1. The entire foot is demonstrated from the distal phalanges to the posterior calcaneus and proximal talus.
          2. The metatarsal bases of the 3rd through 5th digits should be completely free of superimposition.
          3. The joint spaces on all sides of the cuboid should be open.
          4. Radiographic exposure should demonstrate good bone contrast and density throughout the tarsal bones and phalanges. Bone trabeculae and border sharpness must be seen. Soft tissue detail is balanced with bone detail for optimal visualization of the foot.
        • Lateral (Mediolateral) Foot Projection
          1. On an accurately positioned mediolateral radiograph the phalanges, metatarsals, tarsals, and at least 1 inch of the distal leg and all surrounding soft tissues are demonstrated.
          2. The ankle should be in a true lateral with the talar domes superimposed and the fibula partially superimposed by the posterior half of the distal tibia.
          3. The calcaneus is seen in profile with the subtalar and talo-navicular joints opened.
          4. The base of the 5th metatarsal is demonstrated in profile. The articulation of the cuboid and calcaneus is well demonstrated with at least 1 inch of the cuboid distal to the navicular bone.
          5. Standing views will demonstrate weight-bearing projections of the medial and lateral longitudinal arches as well as good bone anatomy.
          6. Optimal radiographic exposure demonstrates good trabecular bone detail and sharp cortical bone lines. All surrounding soft tissue detail must be visualized along with the posterior pericapsular and anterior pretalar fat pads.
        Always ask, "Have I met the diagnostic criteria for this view?”

        Diagnostic Criteria for the Phalanges

        The phalanges of the foot, often called the toes, are commonly imaged in radiology departments and clinics. Although the toes are part of the foot it is better to image them separately when they are the focus of evaluation. This is because the digits are positioned differently than the foot for maximum diagnostic value. Special considerations when imaging the toes are that there is minimal soft tissue overlap of the lateral margins of the phalanges, and that the interphalangeal joints are open or at least not superimposed at their articulation. This requires alignment of the beam with the interphalangeal joint rather than with the tarsal bones. This will be come more apparent during our critique of toe radiographs. A goal for imaging the toes is to isolate the affected toe(s).

        Standard radiographs used to diagnose toe injuries are the AP, oblique, and lateral views. It is important that good bone detail, particularly sharp bone borders are demonstrated. Sharp subject contrast is necessary to properly diagnose some presentations, for example, a normal apophysis of the proximal fifth metatarsal can simulate a fracture. This apophysis is longitudinally oriented and normally fuses by age 16 years. Characteristically it will be present on comparison views of the opposite foot. Another example is the sometimes occurring fibular accessory bone, or a Vesalius accessory bone can be found at the base of the 5th metatarsal. These can be differentiated from a fracture by its smooth sclerotic margins.

        Fractures, dislocations, and foreign bodies are common reasons for imaging the foot. Sharp images are important in differentiating the type of fracture because treatments of what seems a subtle unimportant difference are in fact very different. A Jones fracture is an avulsion of the base of the fifth metatarsal caused by the pull of the peroneus brevis tendon. This type of fracture is treated with wearing a hard shoe or a walking cast. Jones fractures usually heal completely without incidence. A transverse fracture, which is a diaphyseal fracture, can be problematic because of the high incidence of nonunion. These fractures may need surgical fixation. Dislocations of the foot are also common. The most common areas are the interphalangeal or metatarsophalangeal joints. Central foot dislocations mostly are caused by trauma.

        Foreign bodies can be a cause of substantial potential morbidity following traumatic insult. Wood and glass are more problematic for the technologist to display; however, materials close to the density of metal or bone are more easily visualized. It is important that with foreign bodies that the technologist indicate the entry site using an opaque marker. A minimum of two views at right angles to each other is necessary in order for the radiologist to estimate its depth from the surface and precise location. Selecting the correct exposure technique is just as critical for foreign bodies as for disease processes such as osteoporosis, Paget’s disease, and others.

        Toe radiographs should demonstrate the entire distal, middle, and proximal phalanxes and half of the distal metatarsal bones for digits 2-5. Because the first digit does not have a middle phalanx, the distal and proximal phalanxes and distal one half of the first metatarsal is demonstrated. A true AP view of the toe will demonstrate symmetrical appearance of soft tissue and midshaft concavity on each side of shafts of phalanges and distal metatarsals in question. The toe is extended so that the joint spaces will be opened and the phalanges displayed without foreshortening. The best way to do this is to place a 15-degree radiolucent sponge under the toes to elevate them, or use a 10-15 degree caudal angle. Separate the individual digits so there is no overlapping soft tissue. Interphalangeal and MP joints should appear open indicating correct CR centering and tube angle.

        An optimal radiographic exposure demonstrates good bone detail, fine trabecular markings, sharp bone edges, and soft tissue detail surrounding the phalanges and metatarsals. The toenail should also be seen outlining a well-penetrated distal phalanx. Collimation on four sides of the image in keeping with ALARA should be seen.

          AP Phalanges (Toes)

        1. When properly positioned the AP toe radiograph will demonstrate the entire distal, middle, and proximal phalanxes and half of the distal metatarsal bones for digits 2-5. Because the first digit does not have a middle phalanx, the distal and proximal phalanxes and distal one half of the first metatarsal are demonstrated.
        2. A true AP view of the toe will demonstrate symmetrical appearance of soft tissue and midshaft concavity on each side of shafts of phalanges and distal metatarsals in question.
        3. The toe is extended so that the joint spaces will be opened and the phalanges displayed without foreshortening. The best way to do this is to place a 15-degree radiolucent sponge under the toes to elevate them, or use a 10-15 degree caudal angle. Separate the individual digits so there is no overlapping soft tissue. The CR is perpendicular to the joint spaces for toe imaging, whereas it is angled 15 degrees cephalic for imaging the foot.
        4. Interphalangeal and MP joints should appear open indicating correct CR centering and tube angle.
        5. Optimum radiographic exposure should demonstrate good bone detail, fine trabecular markings, sharp bone edges, and soft tissue detail surrounding the phalanges and metatarsals. The toenail should also be seen outlining a well-penetrated distal phalanx. Collimation on four sides of the image to reflect practicing ALARA should be seen.


        image228


        This radiograph represents a well-positioned AP view of the phalanges (toes). Notice that the DIP, PIP, and MP joints of digits 2 through 5 are opened, and that the IP and MP joints of the great toe are opened. This was achieved by elevating the toes with a 15-degree radiolucent sponge and the CR perpendicular to the 3rd MP joint. Notice the soft tissue detail and preservation of bone detail in all the digits. Labeled structures on the radiograph on the right are: distal phalanx 1st digit (A), DIP first digit (B), proximal phalanx 1st digit (C), MP joint first digit (D), first metatarsal (E), distal phalanx 2nd and 3rd digits (F), 2nd and 4th middle phalanx (G), proximal phalanxes digits 2-5 (H), and MP joint of 5th digit.


        Oblique views of digits 1 through 3 are taken with the foot internally (medially) rotated 30 to 45-degrees. Digits 4 and 5 are imaged with the foot rotated 30 to 45-degrees externally (laterally). Proper rotation of the digit in question will result in reduced object-to-image distance (OID), thus less magnification of the part. Supporting the digit with a radiolucent positioning sponge will reduce motion artifact and improve subject detail.

          Oblique Projection-Medial or Lateral Rotation

        1. An accurately positioned oblique toe will demonstrate the entire distal through proximal phalanx and half of the metatarsal and associated joints in question. There should be no overlap of the digits as they are separated and supported to reduce motion artifact.
        2. Digits 1 through 3 are imaged with the foot internally (medially) rotated 30 to 45-degrees. For digits 4 and 5 the foot is rotated 30 to 45-degrees externally (laterally). Often the phalanges of digits 4 and 5 do not rotate medially and remain in the AP position. Proper rotation of the digit in question will result in reduced object-to-image distance (OID), thus less magnification of the part. Supporting the digit with a radiolucent positioning sponge will reduce motion artifact and improve subject detail. The CR is perpendicular to the joint spaces for toe imaging, whereas it is angled 15 degrees cephalic for imaging the foot.
        3. Correct obliquity demonstrates the concavity on one side of the shafts and overlapping soft tissues of the adjacent digits. Adjacent toes are not superimposed.
        4. Optimum radiographic exposure should demonstrate good bone detail, fine trabecular markings, sharp bone edges, and soft tissue detail surrounding the phalanges and metatarsals. The toenail should be seen outlining a well-penetrated distal phalanx. Tight collimation is desirable.


        image229


        Left Radiograph - medial oblique view of digits 1-3 shows the interphalangeal joints opened with good bone and soft tissue detail. The medial oblique is used to image digits 1 through 3 and either the medial or lateral oblique can be used to image digits 4 and 5. When positioning the patient for the oblique view one should use a 45-degree radiolucent wedge placed under the toes to reduce motion. When the medial oblique is used to demonstrate digits 4 and 5, the phalanges are spaced apart so not to excessively overlap their soft tissues (middle radiograph). The problem with performing the medial oblique for digits 4 and 5 is that the toes do not always rotate medially. Notice that the phalanges are not significantly rotated for digits 1-3 on the middle radiograph (white arrows). The metatarsals do rotate medially, which is why the medial oblique view is used to demonstrate the metatarsal bones.


          Phalanges-Mediolateral or Lateromedial Projections

        1. Phalanges of digit(s) in question is/are demonstrated in a true lateral with little to no superimposition by adjacent digits. Digits 2 through 4 may have some superimposition by adjacent digits when in a true lateral.
        2. The lateromedial projection is taken for the 1st, 2nd, and 3rd digits; and the mediolateral projection is used to demonstrate digits 4 and 5.
        3. Interphalangeal and MP joints should be positioned perpendicular to the CR projecting them open even when superimposed.
        4. Digits 1, 2, and 3 are imaged in the lateral to medial projection with the foot medially rotated until the toe in question is in a true lateral. Digits 4 and 5 are imaged medial to lateral with the toe turned laterally into a true lateral position. Toes are separated using a radiolucent sponge, tape, or a tongue blade so there is minimal superimposition of adjacent structures.
        5. Optimum radiographic exposure should demonstrate good bone detail, fine trabecular markings, sharp bone edges, and soft tissue detail surrounding the phalanges and metatarsals. Close collimation on all sides of the part should be seen, reflecting dose reduction and the practice of ALARA.


        image230


        These two radiographs demonstrate what is to be seen when imaging the fifth and first phalanges of the foot. On the left is the first digit in which the distal, middle, and proximal phalanxes are seen. It is important that the MP joint is also demonstrated (white arrow). On the right is the lateral view of the first digit. It only has a proximal and distal phalanx. The MP joint is also demonstrated at the arrow. When imaging the phalanges it is important that all phalanxes are demonstrated along with their interphalangeal joints and the MP joint formed with the metatarsal.


        Radiograph #156

        image155 This patient dropped a pan on her toes and reported pain that has lasted 3 days. The emergency room physician wanted to evaluate digits 3, 4, and 5 for fracture involving the distal phalanxes. Does this radiograph meet the diagnostic criteria for the AP view of these phalanges?

        Critique of Radiograph #156

        image155

        This radiograph of digits 3, 4, and 5 in the AP projection shows the distal phalanxes in partial flexion. This resulted in their respective DIP, PIP, and MP joints being closed due to overlap at the articulations. It is important that the distal phalanx of each digit is extended when the phalanges are the subject of interest. To extend the toes it is best to place a radiolucent angled wedge (no greater than 15 degrees) under the toes and use a perpendicular CR. Better collimation could have been used to limit radiation exposure to the foot. Only distal one half of the metatarsals should be visualized on the radiograph when the phalanges are specified. The radiographic exposure technique is adequate for the toes, but not optimum. Repeating this projection is not necessary provide the oblique and lateral views are properly positioned.

        Radiograph #157

        image156 This radiograph was taken on a patient who presented to a local clinic with a chief complaint of “toe pain”. Clinical evaluation revealed point tenderness over the second and third distal phalanxes. Does this radiograph meet the diagnostic criteria for the AP and oblique views?

        Critique of Radiograph #157

        image156

        It is important to position each digit of interest using a radiolucent wedge to get the distal joints perpendicular to the CR. Notice on the AP view (left) shows closed joints and soft tissue overlap between the digits. The oblique view (right) shows bone and soft tissue overlap, and motion artifact. This is due to improper spacing of the digits and supporting them on an angled wedge. Because the DIP and PIP joints are not opened both projections should be repeated. The exposure technique shows poor bone detail and blurred trabecular markings. The cortical bone edges are not sharp either. Repeat both projections with special attention to spacing the phalanges and opening the interphanlangeal joint spaces. Using a radiolucent sponge to support the toes will reduce part motion. Better collimation to reduce patient exposure should also be applied.

        Radiograph #158

        image157 This radiograph was taken evaluate the phalanges of digits 1-4. Patient reported dropping metal vase on toes. Clinical exam revealed pain over the 1st, 2nd, and 3rd phalanges and their MP joints. Does this radiograph meet the diagnostic criteria for the oblique view of the toes?

        Critique of Radiograph #158

        image157

        There are at several reasons this radiograph does not meet the diagnostic criteria. The toes are flexed so that the DIP and PIP joints are closed. The distal and middle phalanxes of each digit are foreshortened. The second reason this radiograph should be repeated is that the exposure technique does not demonstrate bone trabecular detail. Neither is the cortical bone edges sharply defined. In addition, this a less than optimal radiograph because there is no collimation of the part. Close collimation in this case would be to limit the exposure to one half of the metatarsals. It is customary that digits 1-5 are imaged when an area as clinically described injured. However, the tarsal bones and the proximal half of the visualized metatarsals should have been omitted.

        Radiograph #159

        image233 The clinical history for this patient is “stubbed toe on a bed post.” The pain got worse over a 6-hour period prior to presentation at the local emergency room. This radiograph was taken to evaluate the distal phalanx of the fifth digit. Do these three views (AP, medial oblique, and lateral) meet their respective diagnostic criteria for the toe?

        Critique of Radiograph #159

        image233

        This radiograph contains three views of the fifth toe: AP view (left), medial oblique (middle), and lateromedial-lateral (right). All three views demonstrate the required anatomy (from the distal one half of the metatarsal through the distal phalanx and all surrounding soft tissues). The DIP and PIP joints are closed and the middle and distal phalanxes foreshortened. The MP joints are open and properly positioned on all views. There is good bone detail on all views showing good trabecular markings and sharp cortical bone borders. The lateral view demonstrates the distal and proximal phalanxes and the MP joint free of superimposition.

        Radiograph #160

        image234 The clinical history for this patient is “stepped on something and the pain won’t stop.” Clinical evaluation revealed a small puncture on the plantar side of the distal phalanx of the 1st digit. The radiographic request was to evaluate left 5th toe. Does this radiograph meet the diagnostic criteria for the toe in question?

        Critique of Radiograph #160

        image234

        A major issue with these radiographs is that there is poor collimation of the part. Only the distal half of the metatarsal is required when imaging the toe. In keeping with ALARA it would be better to collimate to the area of interest thereby reducing patient exposure. Using an arrow or metal pointer to indicate the location of the puncture will further emphasize the correctness of using tight collimation. Positioning of the AP and oblique views properly demonstrate the interphalangeal and MP joints. The lateral view does not meet its diagnostic criteria. The fifth digit must be separated from the others, and greater kVp is needed to penetrate it. Also use a pointer to indicate the site of the puncture wound and use tight collimation limited to half of the metatarsal to bring out subject detail. The patient does not need to hold the toes, using a tongue blade or tape is recommended. These changes will make this a better lateral view when repeated.

        Summary of the Diagnostic Criteria for the Phalanges

        • AP Phalanges (Toes)
          1. When properly positioned the AP view will demonstrate the entire distal, middle, and proximal phalanxes and half of the distal metatarsal bones for digits 2-5. Because the first digit does not have a middle phalanx, the distal and proximal phalanxes and distal one half of the first metatarsal are demonstrated.
          2. A true AP view of the toe will demonstrate symmetrical appearance of soft tissue and midshaft concavity on each side of shafts of phalanges and distal metatarsals in question. The toe is extended so that the interphalangeal joint spaces are opened and each phalanx is displayed without foreshortening. Interphalangeal and MP joints should appear open indicating correct CR centering to the joint spaces. The individual digits are separated so there is minimal overlap of soft tissue.
          3. Optimum radiographic exposure should demonstrate good bone detail, fine trabecular markings, sharp bone edges, and soft tissue detail surrounding the phalanges and metatarsals. Collimation on four sides of the image should be seen reflecting the practice of ALARA.


        • Oblique Projection-Medial or Lateral Rotation
          1. An accurately positioned oblique toe will demonstrate the entire distal through proximal phalanx and half of the metatarsal and associated joints in question. There should be no bone overlap of digits as they are separated to show good spacing. Support the toes with a radiolucent sponge to eliminate motion artifact and improve subject detail.
          2. Digits 1 through 3 are imaged with the foot internally (medially) rotated 30 to 45-degrees. For digits 4 and 5 the foot is rotated 30 to 45-degrees externally (laterally). Proper rotation of the digit in question will result in reduced object-to-image distance (OID), thus reduce magnification of the part.
          3. Correct obliquity is demonstrated by increased concavity on one side of the shafts and by overlapping soft tissues of the adjacent digits. Optimum radiographic exposure technique is the same as for the AP view.


        • Lateral-Mediolateral or Lateromedial Projections
          1. Phalanges of digits in question should be seen in a true lateral with little to no superimposition by adjacent digits. Digits 3-5 will be seen in a true lateral with some superimposition of other digits.
          2. The lateromedial projection is taken for the 1st, 2nd, and 3rd digits; and mediolateral for digits 4 and 5.
          3. Each digit in question should be seen in a true lateral with little to no superimposition by adjacent digits. Digits 3-5 will be seen in a true lateral with some superimposition of other digits. The interphalangeal and MP joints are projected open even when superimposed.
          4. The lateromedial projection is taken for the 1st, 2nd, and 3rd digits; and mediolateral for digits 4 and 5. The toes are separated using a radiolucent sponge, tape, or a tongue blade so there is minimal superimposition of adjacent structures.
          5. Optimum radiographic exposure should demonstrate good bone detail, fine trabecular markings, sharp bone edges, and soft tissue detail surrounding the phalanges and metatarsals. Collimation on four sides of the image should be seen reflecting the practice of ALARA.
        Always ask, "Have I achieve the diagnostic criteria for each projection?"

        Diagnostic Criteria for Imaging the Heel

        The calcaneus is the most frequently fractured bone of the foot. Injury to the calcaneus usually occurs due to a fall from height. Calcaneus fracture is a debilitating injury because these often involve the subtalar joint and therefore chronic pain and arthritis are the results. The heel is composed mostly of cancellous (a.k.a. spongy bone), which makes it more difficult to heal. Standard radiographs of the heel include the axial (Plantodorsal) and the mediolateral projections. When imaging the calcaneus it is important that the trabecular pattern is clearly seen and the talocalcaneal joint and sustenaculum tali are demonstrated on both views.

          Axial (plantodorsal) Projection

        1. A correctly positioned axial view of the calcaneus will demonstrate an open talocalcaneal joint and good penetration of the sustenaculum tali.
        2. The CR is aligned to the axial heel by placing the foot in a vertical position and directing the tube 40-degrees cephalad, toward the plantar surface. The ankle is placed in a true AP position to avoid tilt or rotation of the heel. The CR should be parallel with the talocalcaneal joint space and perpendicular to the calcaneal tuberosity. A good landmark is for the angle to pass through the heel at the height of the base of the 5th metatarsal through the distal tip of the lateral malleolus.
        3. The bases of the 1st and 5th metatarsals should not be seen on ether side of the heel when it is not rotated. A portion of the sustentaculum tali should be in profile on the medial side of the heel.
        4. A well-penetrated axial view will demonstrate an open talocalcaneal joint space and well-defined bone structure of the calcaneal tuberosity. Close collimation is needed to display optimal subject detail and contrast.


        image231


        The radiograph on the left demonstrates the correct positioning and penetration of the heel for the axial calcaneus view. The talocalcaneal joint is well-penetrated (A) as is the sustentaculum tali (B). Notice that the metatarsals are not seen indicating the foot is not rotated. The axial CT image on the right also demonstrates the talocalcaneal joint (A) and sustentaculum tali (B). The calcaneus (C) shows good trabecular pattern in both views.

          Lateral heel Projection

        1. Structures demonstrated on the lateral calcaneus view are: an open tibiotalar joint, the entire talus and calcaneus. The calcaneal articulations with the talus, navicular, and cuboid bones should be clearly seen. Four-sided collimation should include the base of the 5th metatarsal anteriorly, the ankle joint superiorly, the entire posterior soft tissues of the heel, and all soft tissue of the visualized foot inferiorly.
        2. When accurately positioned heel, the will demonstrate superimposed talar domes with the calcaneocuboid joint and tarsal sinus opened. The fibula should be superimposed on the posterior half of the tibia.
        3. Optimum exposure will demonstrate the distal fibula through the talus, sharp trabecular calcaneal markings, and all soft tissues surrounding without burnout.


        image232


        This lateral radiograph of the heel demonstrates the proper penetration of the part and structures that are demonstrated by diagnostic criteria. Structures demonstrated are: distal talus (A) superimposed posteriorly by the fibula (B), tibiotalar joint (C), talus (D), navicular (E), cuboid (F), base of fifth metatarsal (G), calcaneus (H), and talocalcaneal joint (I). Notice that the exposure technique clearly shows the trabecular pattern of heel and surrounding soft tissue is properly visualized without “burnout.”

        Now let’s review a few radiographs of the heel using the diagnostic criteria for the axial and lateral views.

        Radiograph #161

        image159 This radiograph of the heel was requested as a standing view because of possible bone spur. Does this radiograph meet the diagnostic criteria for the lateral projection of the calcaneus?

        Critique of Radiograph #161

        image159

        This weight-bearing horizontal beam lateral shows the heel, longitudinal arch, ankle joint, and sinus tarsi very well. Bone trabecular pattern is well demonstrated in the calcaneus and other visualized bones. Because the heel is in question the only structures that should be demonstrated on a well collimated field are: the distal most portions of the tibia and fibula, an open tibiotalar joint, talus, calcaneus, and all articulations of the calcaneus with other tarsal bones, and all surrounding soft tissue. While this radiograph meets the diagnostic criteria, it fails to meet standards for ALARA because of poor collimation.

        Radiograph #162

        image160 Does this radiograph of the heel in the axial projection meet the diagnostic criteria?

        Critique of Radiograph #162

        image160

        The radiographic exposure technique is very good. The entire heel and its articulations are seen without burn out of the calcaneal tuberosity. The bone trabecular pattern is also seen. The sustentaculum tali, trochlear process, and calcaneal tuberosity are well visualized on this radiograph. The talocalcaneal joint is seen opened. The correct amount of tube angle (40 degrees) is used to project the heel without distortion of the calcaneal tuberosity. The foot is properly dorsiflexed with the plantar surface vertical to the CR. The fourth and fifth metatarsals are demonstrated laterally The leg should be internally rotated until the ankle is in a true AP projection. This radiograph should not be repeated in keeping with ALARA!

        Radiograph #163

        image235 Does this radiograph of the calcaneus meet the diagnostic criteria for the plantodorsal projection?

        Critique of Radiograph #163

        image180

          The major reason this digital radiograph should be repeated is that the heel is elongated and the talocalcaneal joint is obscured. This is due to the tube angle being greater than 40 degrees and the CR entering higher than at the fifth metatarsal base. It looks like the CR entered near the heads of the metatarsals. Notice the poor collimation, which reduces subject contrast due to image noise. The foot and ankle do not appear to be rotated as the metatarsals are not projected laterally to the heel. While this may appear to be an acceptable radiograph, it is not and should be repeated. The talocalcaneal joint must be demonstrated opened using the proper tube angle and entry for the CR.

        Radiograph #164

        image236 This post-operative radiograph of the heel was taken to evaluate fixation of a torn ligament to the heel. A true lateral was requested. Does this radiograph of the calcaneus meet the diagnostic criteria for the plantodorsal projection?

        Critique of Radiograph #164

        image236

        This is the most common type of misalignment of the calcaneus seen radiographically. Notice that the fourth and fifth metatarsals are demonstrated laterally. The cause of this is external rotation of the leg. Internally rotating the leg will correctly align the heel to demonstrate all parts of the talocalcaneal joint opened, and the sustentaculum tali in profile. The correct tube angle was used since the calcaneal tuberosity is not elongated or foreshortened. The exposure technique correctly demonstrated the tuberosity without burnout and the joint spaces of the heel well penetrated. The talocalcaneal joint space is closed; however the calcaneal tuberosity is elongated. This indicates the foot is dorsiflexed beyond vertical. Repeat this radiograph repositioning the foot vertical with internal rotation.

        Summary-Diagnostic Criteria for Imaging the Heel

        • Axial (plantodorsal) Projection
          1. A correctly positioned axial view of the calcaneus will demonstrate an open talocalcaneal joint space and good penetration of the sustenaculum tali.
          2. Align the CR towards the plantar surface at an angle of 40-degrees. The foot vertical at 90 degrees to the leg. The ankle is placed in a true AP position to avoid tilt or rotation of the heel. The CR should be parallel with the talocalcaneal joint space and perpendicular to the calcaneal tuberosity. A good landmark is for the angle to pass through the heel at the height of the base of the 5th metatarsal passing through the distal tip of the lateral malleolus.
          3. No rotation should be seen. The bases of the 1st and 5th metatarsals should not be seen on ether side of the heel. A portion of the sustentaculum tali should be in profile on the medial side of the heel.
          4. A well-penetrated axial view will demonstrate an open talocalcaneal joint space and well-defined bone structure of the calcaneal tuberosity. Close collimation is needed to bring out subject detail and contrast.
        • Lateral heel Projection
          1. Structures demonstrated on the lateral calcaneus view are: an open tibiotalar joint, entire talus, entire calcaneus, and calcaneal articulations with the talus, navicular, and cuboid bones. Four-sided collimation should include the base of the 5th metatarsal anteriorly, the ankle joint superiorly, the entire posterior soft tissues of the heel, and all soft tissue inferiorly.
          2. An accurately positioned heel will demonstrate superimposed talar domes. The calcaneocuboid joint space and the tarsal sinus should appear open. The posterior half of the tibia should superimpose the fibula.
          3. Optimum exposure will demonstrate the distal fibula through the talus, sharp trabecular calcaneal markings, and all soft tissues surrounding visualized bone.
        Always ask, "Did I achieve the diagnostic criteria for the view that I am taking?"



        Copyright image Copyright 2004-2008 Nicholas Joseph Jr.




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